《剑指offer - 题目2》

题目描述

请实现一个函数，将一个字符串中的每个空格替换成“%20”。例如，当字符串为We Are Happy.则经过替换之后的字符串为We%20Are%20Happy。

 

注意方法参数中没有返回值，直接在原来的缓冲区中修改就可以了

 

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#include <stdio.h> #include <stdlib.h> #include <string>   /* 题目描述 请实现一个函数，将一个字符串中的每个空格替换成“%20”。例如，当字符串为We Are Happy.则经过替换之后的字符串为We%20Are%20Happy。 */   //从后面往前面开始复制   using namespace std;   class Solution { public:     void replaceSpace(char *str,int length) {         char *head = str;         int chrLength = 0;         int spaceLength = 0;                   while (*head) {             if(*head == ' '){                 spaceLength++;             }             else{                 chrLength++;             }             ++head;                       }         if(spaceLength*2 + chrLength + 1 > length)             return;         int strLength = chrLength + spaceLength;         char *tail = str + chrLength + spaceLength - 1;         char *newTail = str + spaceLength*3 + chrLength;         *newTail-- = '\0';         while (strLength >= 0) {             if(*tail == ' '){                 *newTail-- = '0';                 *newTail-- = '2';                 *newTail-- = '%';             }             else{                 *newTail-- = *tail;             }             tail--;             strLength--;         }     } };